1. Field of the Invention
This invention relates to a cell surface polypeptide of Porphyromonas (Bacteroides) gingivalis (another name; periodontopathic organism: hereinafter, referred to as Porphyromonas gingivalis) having a molecular weight of about 72-kDa (kilodalton) (hereinafter abbreviated as periodontopathic organism cell surface polypeptide), a DNA encoding the polypeptide, a recombinant DNA wherein the DNA is integrated and a microorganism containing the recombinant DNA.
The DNA obtained in the invention can be utilized as a reagent, namely as a probe for detecting Porphyromonas gingivalis. Further, the periodontopathic organism cell surface polypeptide obtained in the invention and produced by a microorganism can be utilized for a diagnosis of patients suffering with periodontal diseases and having antibodies against Porphyromonas gingivalis, as an antigen for preparing an antibody for diagnosing patients suffering with periodontal diseases and having Porphyromonas gingivalis or as a prophylactic vaccine for periodontal diseases.
2. Description of Related Art
It is reported by Yoshimura et al. in Infect. Immun., 57, 3646 (1989) that since the periodontopathic organism cell surface polypeptide exhibits strong immune response to the sera of patients of periodontal diseases, infecting with Porphyromonas gingivalis, antibodies against the polypeptide existing in the sera of the patients can be detected using it. Further, it is reported by Ogawa et al. in Nippon Saikin-gaku Zasshi, 44, 329 (1989), by Yoshimura et al. in J. Bacteriol., 160, 949 (1984) and by Yamaji et al. in Nisshishushi, 33, 349 (1991) that the immune response of the polypeptide is different from that of the known fimbrial protein from the known periodontopathic organism having a molecular weight of 41 kDa, and thus the periodontopathic organism cell surface polypeptide of the invention is different from the ciliary protein.
As to the structure of the periodontopathic organism cell surface polypeptide, its amino acid composition is reported by Yoshimura et al. in Infect. Immun. 57, 3646 (1989), and the amino-terminal amino acid sequence of a purified polypeptide thereof is reported by Yoshimura et al. in FEMS Microbiol. Lett., 92, 47 (1992). Elucidated amino acids are 40 amino acids, and when we compare 40 amino acid with an amino acid number estimated from the molecular weight of the periodontopathic organism cell surface polypeptide, the rate is only under 10%. Further, concerning with a DNA encoding the periodontopathic organism cell surface polypeptide, it is reported by Yoshimura et al. in FEMS Microbiol. Lett., 92, 47 (1992) that its part was obtained. However the base sequence of the gene is not elucidated at all.
The periodontopathic organism cell surface polypeptide is recovered from Porphyromonas gingivalis cells, but its supply amount is limited because of difficulty of the culture of Porphyromonas gingivalis. Thus development of an industrial process for supplying the periodontopathic organism cell surface polypeptide is desired.